Question 21M.2.SL.TZ1.7c
| Date | May 2021 | Marks available | [Maximum mark: 4] | Reference code | 21M.2.SL.TZ1.7c |
| Level | SL | Paper | 2 | Time zone | TZ1 |
| Command term | Discuss | Question number | c | Adapted from | N/A |
Discuss the relationship between atmospheric carbon dioxide concentration and global temperatures.
[4]
a. greenhouse effect keeps Earth warm ✔
b. (over-time) earth’s temperature has fluctuated naturally ✔
c. changes in human activities have led to increases in CO2 concentration ✔
d. CO2 absorbs infrared/long wave radiation / trapping heat ✔
e. increase in atmospheric CO2 (concentration) correlates with/causes increased global average temperature ✔
f. use of fossil fuels increases atmospheric CO2 ✔
g. deforestation removes a carbon sink / less CO2 absorbed ✔
h. loss of polar ice causes less reflection of surface light/ more reradiation as heat contributing to (global) warming ✔
i. CO2 is not the only greenhouse gas/ there are other greenhouse gases ✔
This question was attempted by approximately 56 % of candidates.
This question was actually quite narrow as reflected in the number of marks it could earn. Some candidates understood which part of the global warming topic was being asked of them and stuck to the topic. Good applications to the carbon cycle were given. Strong responses avoided deviations into consequences and how humans should behave. Several misunderstandings surfaced. For example that CO2 was responsible for the breakdown of the ozone layer. Many seemed to tie ozone layer destruction and global warming information together in their explanation. Atmospheric carbon dioxide and the ozone layer were confused. Some thought that the ozone layer traps heat.
